Fluid motor



Aug- 15, 1939. H. F. PARKER 1 -6924151 FLUID MOTOR y Filed 1; e0 .3I1955 5 She ets-Sheet l //ak i ,74 /54 62 ai; ,450 62 64 ATTORNEYS.

Aug. 15, 1939. F, PARKER 2,169,451 I FLUID MOTOR svga .9) f

@i @EL INVENTOR. Hump/:rag 7:'r )Par/Tfn ATTORNEYS.

FLUID MOTOR Filed'nec. s, 193s l5 sheets-Sheet s EL?. ,2. u

' ATTORNEYS.

Aug. l5, 1939. H. F. PARKER 2,169,451

FLUID uoTon Filed'Dec. 3, 1936 5 Sheets-Sheet 4 ZZ 122g Y INVENTOR./fzzmyZr-ey 777%716'7:

, BY v ywn Y ATTORNEYS.

Aug. 15, 1939. I H F, PARKER 2,169,451

FLUID MOTOR ai? Y 5l 35 "32 H INVENTOR. iwf/Fre! Frer:

ATTORNEY.

Patented Aug. 15, 1939vv UNITED STATES TENT OFFICE 23 Claims.

The present invention relates` to fluid pressure operated motormechanisms, and in partiuular provides improved fluid pressure operatedmotor mechanisms characterized in that the motor may automatically bebrought to rest in a selected position of the movement thereof.

The co-pending application of the present applicant Serial No. 106,134,filed October 17, 1936, discloses fluid pressure operated motormechanisms of the general type to which the motor mechanisms of thepresent invention relate. 1n the `cci-pending structures, the fluidpressure motor comprises generally an oscillatable vane or areciprocable piston, movable between predetermined limits by thealternate application of iiuid pressure to the opposite sides of thevane or piston. The alternate application of fluid pressure iscontrolled by a reversingr valve adapted to be moved to one limitposition by the application of fluid pressure thereto, and adapted to bemoved to the other position by a compression spring, upon the exhaustionof the just mentioned fluid pressure. In order to bring the vane orpiston to rest in a predetermined position in its stroke,

preferably of one of the limit positions, parking means are providedwhich respond to the position of the vane or piston. The parking meansare illustrated in the (3o-pending application as taking the form of avalve disposed to prevent completion of a fluid supply circuit to thereversing valve, so that, upon reaching one of the limit positions, thevalve fails to reverse, and the vane or piston consequently remains atrest in the limit position. The co-pending construction also embodiesalternative arrangements by which the vane or piston may be caused toassume a parking position beyond the normal limit of its travel, as Wellas means incorporated in the parking valve for controlling the motorspeed.

In accordance With the present invention, it is preferred toeffect theparking of the vane or piston by cutting 01T the supply of fluidpressure thereto, the cut-off mechanism being so arranged that it isrendered effective only when a limit position of the vane or piston isreached, or alternately, when the vane or piston has been permitted tomove to a position-slightly beyond its normal limit of travel. 1n thepreferred construction, the cut-off mechanism takes the form of asupplemental valve of the fluid pressure actuated type, suitablypositioned Within the motor and arranged to control the uid pressuresupply circuit leading to the piston or vane chamber.

The control valve is arranged for selective control by a parking or stopValve and also by the position of the vane or piston.

With the just stated as well as other imp-rovements in View, objects ofthe present invention are to provide a fluid pressure operated motormechanism, embodying a movable vane or piston, and embodying improvedmeans for cuttingv off the supply of pressure to said vane or pistonWhen in a selected position; to provide such a construction in which thestopping of the motor may be caused to occur either at a normal limitposition of the vane or piston or at a position thereof beyond a normallimit; to provide such a motor construction which may embody speedregulating mechanism for controlling the normal 15 operation oi themotor; to provide such a system in which the cut-oli mechanism embodiesa supplemental valve of the uid pressure operated type, arranged tocontrol the supply of fluid pressure to the vane or piston chamber; tcprovide such a system in which the movements of the supplemental orcut-off valve are jointly controlled by a selectively operable parkingdevice and by the position of the motor vane or piston, so that theparking device may be operated at 25 any time independently of theposition or direction of travel of the vane or piston; and to pro videsuch a mechanism embodying main Fluid passages adapted to control thenormal operation of the vane or piston and of the various valves 30 andalso embodying secondary passages for preventing `faulty operationthereof.

Further objects of the present invention to provide a iluid pressureoperated motor mecha` nism embodying characteristics of the above gen35` erally stated character, `Which may be readily and economicallymanufactured, assembled and installed and which is positive and reliablein operation.

With the above, as Well as other and more dem 40 tailed objects Whichappear in the following dcscription and in the appended claims,preferred but illustrative embodiments of the present invention areshown in the accompanying draW- ings, throughout which correspondingreference 45 characters are used to designate corresponding parts. andin which:

Figure 1 is a View in rear elevation of a motor of the vane typeembodying the invention;

Fig. 2 is a view in end elevation of the motor 50 shown in Fig. 1;

Fig. 3 is a view in vertical section taken along the line 3--3 of Fig.2;

Fig. 4 is a fragmentary View of the underside of the motor of Figs. 1and 2 55 Fig. is a View in vertical section, taken along the line 5 5 ofFig. 3;

Fig. 6 is a view in vertical section, taken along the line 6--6 of Fig.5;

Fig. '7 is a fragmentary view in vertical section, taken along the line'1 -1 of Fig. 6,'

Fig. 8 is a view in horizontal section, taken along the line 8--8 ofFig. 1;

Fig. 9 is a View in vertical section, taken along the line 9 9 of Fig.5;

Fig. 10 is a fragmentary View in vertical section, taken along the lineIIJ- I0 of Fig. 6;

Fig. 11 is a View in vertical transverse section,

Y of a modified construction of the invention, em-

bodying means for selectively controlling the speed of the motor;

Fig. 12 is a view in vertical section, taken along the line |2|2 of Fig.11 and showing the cutolf and speed control device in the parkingposition;

Fig. 13 is a view in Vertical section, taken along the line |3--3 ofFig. 11;

Figs. 14 and 15 are views corresponding to Fig. 12, but showing thecombined parking and speed control device in the fast and slow speedposition respectively;

Figs. 16 and 17 are views in vertical section of a further modificationof the present invention, in which the motor vane may be automaticallyparked in a position beyond its normal limit of travel, and showing theparts in the operating and parked positions respectively;

Fig. 18 is a fragmentary schematic view based upon the construction ofFigs. 16 and 17;

Fig. 19 is a view in rear elevation of a motor embodying a modifiedconstruction of supplement cut-off valve;

Fig. 20 is a fragmentary view in vertical section of the motor shown inFig. 19;

Fig. 21 is a view in vertical section, taken along the line 2|-2'IofzFig. 20;V

Fig. 22v is a view in vertical section, taken along the line 22--22 ofFig. 20;

Fig. 23 is a View in horizontal section, taken along the line 23-23 ofFig. 22; Y

Fig. 24 is a view in horizontal section, taken along the line 24-24 ofFig. 21;

Fig. 25 is a viewY in end Yelevation of a piston type motor embodyingthe invention;

Fig. 26 is a view in horizontal section taken along the line 26-25 ofFig. 25;

Fig. 27 is a view in horizontal section taken along the line 21-21 ofFig. 25; Y

Fig. 28 is a view in vertical section taken along the line 28-28 of Fig.26;

Fig. 29 is a view in vertical section the line 29--29 of Fig. 26;V y YFig. 30is a view in Vertical section taken along the line 30-30 ofy Fig.26; 'Y

Fig. 31 is a View in vertical section taken along the line 3l-3IY ofFig. 29;

Fig. 32 is aview in vertical section taken along the line 32-32 of Fig.l29; and,

Fig. 33 is a view in vertical section taken along the line 33--33 ofFig. 29.

Referring first to the embodiment shownin Figs. 1 through 10, the motordesignated as a whole as 50, comprises two castings 52 and 54, suitablysecured, as by the studs 56, in back to back relation. VThe two castings52 and 54 t0- gether define a piston chamber 58 -of generallysemi-circular shape, within vwhich a vane-60, secured to Ya shaft 62, isreciprocable under the infiucnce of fluid pressures alternatelyapplied'to the opposite faces thereof in the manner hereintaken alongafter described. The right-hand end 64 of shaft 62, as viewed in Fig. 5,projects outwardly of the casting 54, and may be suitably connected tothe mechanism to be actuated by the oscillation of the vane 60. Arepresentative application of the present invention is in connectionwith the operation of vehicle windshield wipers, and in suchapplications the motor may either be mounted adjacent the windshield orremotely therefrom, as in the engine compartment. Where oil is used asthe motive fluid, the engine compartment mounting is preferred, and thetransmission between the motor and the wiper or wipers may take the formdisclosed in the co-pending application of the present applicant, SerialNo. 102,- 098, filed September 23, 1936. In the co-pending construction,the projecting end 64 of the shaft 62 of Fig. 5 of the presentapplication is provided with a pinion in continuously meshing relationto a pair of oplpositely disposed racks which are connected by flexiblecables or Bowden Wires to the wiper or wipers. rlfhe oscillation of theshaft effects corresponding oscillatory movements of the racks which aretransmitted to the wipers themselves as oscillatory movements.v Asshown, the casting 54 is provided with portions 66 which denes a recesswithin which the just mentioned racks may move. It will be appreciated,however, that the motor may be associated with transmission systemsother than the just mentioned transmission system, and may be used inmany applications other than the windshield wiper Systems. Theright-hand side of the casting 52, a viewed in Fig. 2, is preferablymachined to provide a face 68, through which the motor 5U may be securedto suitable supporting structure. In instances Where the improved motorof the present invention is used in connection with the operation of thewindshield wiperV of a vehicle and oil is used as the motive fluid, themotor may be mounted adjacent the vehicle engine, iand the face 68positioned in engaging relation toa pad 69 provided on the block of theengine, which mounting simplifies the problem of delivering oil from theoil pressure system of the motor and returning the oil from the motor tothe crank case.

In the illustrated embodiment of the invention, the valve mechanisms forautomatically' controlling the starting, stopping and reversing of thevane 62, comprise a piston type fluid pressure actuated reversing valveT0, which controls the application of uid pressure to the opposite facesof vane a cut-off valve 12 ofthe fluid pressure actuated type which ashereinafter described, may be automatically controlled to shut 01T thesupply of fluid pressure to theV motor 50; yand a manual or parkingvalve 14.

The reversing valve 'lil is slidable in a suitable passage providedtherefor in the casting 52, the otherwise open end of which is closed bya suitable removable plug 16. The valve passage space I8 between theplug 16 and the end of valve 10 forms what is hereinafter referred to asa valve actuating chamber, to which the oil or other motive fluid isselectively introduced and 'exhausted as hereinafter described. As willbe ap- .l preciated, introduction of fluid pressure into the chamber I8Vforces valvel to the left as viewedv end of the'va-lve passage.Exhaustion of the 75 fluid from the chamber 18 permits the spring toforce valve 10 to the illustrated or extreme right-hand position inwhich the stop 82 provided on the end of the valve body abuts the plug16. The valve l0 is provided with two annular recessed portions 84 and85, separated by a land 88 of larger radius, which two recessed portionsalternately connect opposite sides of the vane to the source of uidpressure and to exhaust, as hereinafter described.

The cut-off valve l2, most clearly shown in Fig. 6, is received in asuitable passage provided therefor in the casting 54, and comprises aneedle valve portion 90 which seats against a seat 9| formed in one ofthe fluid passages, and, as hereinafter described, is disposed todirectly control the admission of iiuiclV pressure to the reversingvalve l0 and consequently to the vane chamber. Valve 'l2 is providedwith a reduced portion 92, which, with an adjacent enlarged portion 54,forms a supplemental valve actuating chamber into which fluid pressuremay be introduced to move valve 'l2 to the left, to the open positionthereof, permitting the motor to start and operate. As hereinafterdescribed, the fluid pressure may also be selectively exhausted from thechamber 96, thereby rendering a compression spring 98, which surroundsthe body of valve l2, to force valve 'i2 to the illustrated closedposition, the spring 9S is seated between the enlarged portion 94 and aplug |00 which closes the otherwise open end of the passage provided forin valve 12.

The manual valve 14, most clearly shown in Fig. 6, is illustrated asalso being of the piston type, provided with a recessed portion |02,separated by two enlarged portions |04 and |00. Valve i12 is freelymanually slidable in a passage provided therefor in the casting 54, andis illustrated in Fig. 6 in the stop position thereof. In this positionthe portion |06 closes off the fluid Jressure supply circuit to thecut-off valve actuating chamber 90, and prepares an exhaust circuit forthe chamber 06, as described in detail hereinafter. The actuating meansfor valve 14 is not illustrated but, as will be appreciated, may takeany convenient form such as a flexible cable or wire, the connector forthe casing of which may be suitably secured to the casting 54 v Theremaining mechanical details of the motor, including the various supplyand exhaust passages involved in the fluid circuits associated with thevarious valves and with the Vane chamber, may be best understood inconnection with a, description of operation of the moto-r as a whole.Throughout the following description, only the active fluid passages arereferred to and given the reference characters. Any uid passages shownin the drawings and not given reference characters are dead-endpassages, closed by removable plugs, and formed as an incident to theformation of the active passages', as will be understood.

The parts are shown in the stopped position, that is manual Valve '|4occupies its left-hand limit position in which it prepares a iuidexhaust circuit for the chamber 90 associated with the cut-oi valve l2;valve l2 is in its shut off position in which the supply of uid to thevane chamber 56 is interrupted; vane 60 is in its righthand limit o-ftravel, in a parked position; and reversing valve 'i0 is in itsright-hand position.

To place the motor 50 in operation, the manual valve i4 may be moved tothe right (Fig. 6) so that the recess |02 thereof registers with both ofthe pasages I0 and 2, thus completing a uid pressure supply circuit forthe Valve chamber 96. This fluid pressure supply circuit extends fromthe inlet i4 (which may be connected to a source of iiuid pressure, suchas the pressure lubrication system of a vehicle, in any suitable way),through the passage I 2, around the recess |02, and through the passages||0 and ||6 into the chamber 95. Completion of this circuit results inthe building up of a pressure within the chamber 95, forcing cut-offvalve T2 to the left as viewed in Fig. 6 against the force of thecompression spring 08.

The movement to the left of valve 12 moves the needle Valve portion 90thereof out of seating relation to the seat 9|, thereby completing afluid supply circuit to the reversing valve actuating chamber 'i3 andalso completing a fluid pressure supply circuit leading through thevalve 10 into the portion of chamber 58 at the left-hand side of vaneSii.

The fluid pressure supply circuit for the valve actuating chamber 13extends from the inlet ||4 through the passage l l2, connecting passageI8, vert-ical connecting passage |20 to a recess |22 formed in the motorshaft 62. This recess is arranged to register with the vertical passage|20 only when the vane 6 is in, its illustrated righthand limitposition, for a reason which will presently appear. From the recess |22,the uid circuit extends through a vertical passage |24,

which registers with the recess when the vane is in the right-hand limitposition, and then through passages |26 and |28 into the valve chamberiii. The just traced fluid circuit is one that is completed at eacharrival of the vane 60 at its right-hand limit position. As describedhereinafter, however, each stopping operation cuts off the supply offluid to valve chamber 18, which cut-off usually occurs before asubstantial pressure is built up within chamber 18. With motor 50 atrest, accordingly, valve l0 normally may be expected to occupy itsrighthand position, but compieticn of the above circuit which With valvel0 in the left-hand position, a fluid pressure supply circuit iscompleted for the portion of chamber 5S to the right of the vane 00 anda fluid exhaust circuit is completed for the portion of chamber 58 tothe left of the vane60. The fluid pressure supply circuit extends fromthe inlet lit, through the passages ||2 and ||8, around the valve seat9|, and thence through a lateral main supply passage |30 to valveg10.From passage E30, the circuit extends around the recess 553 of valve i@and through passage |32 into the chamber 5S. The fluid exhaust circuitextends from the portion of chamber 58 to the left of vane 50 throughthe passage: |34, around the recess 85 of valve it and thence through anexhaust port |36 intov the sump. As previously stated, where the motor50 is secured to the block C59 of a vehicle engine, the exhaust passage|36 may be directed through the wall of the block into the vehicleengine crank case.

During completion of the just traced two circuits, accordingly, vane 50is acted upon by a 75 differential pressure which causes it to move in acounter-clockwise direction, as viewed in Fig. 3. The initial movementof vane 60 away from the position illustrated in Fig. 3 moves the shaftrecess |22 out of registry with the passages |20 andv |24, interruptingthe previously traced fluid pressure supply circuit for the valveactuating Y chamber 18. This action is without effect, however, exceptto trap the previously delivered fluid within the chamber, which trappedfluid retains valve in its yillustrated right-hand limit position.

As vane 60 approaches its left-hand limit of travel, a radial passage|40 formed in shaft 62, is brought into registry with the previouslydescribed passage |24, thereby completing an exhaust circuit for thevalve chamber 18. This exhaust circuit extends fro-m chamber 18 throughthe passages |28, |26 and |24 into the radial shaft passage-|40. Theradial shaft passage |40 communicates with an axial passage |42 whichleadsdirectly to the sump, and through which the fluid previouslytrapped within the chamber 18 may freely flow. Accordingly, uponcompletion of the above traced circuit, the spring 80 associated withvalve 10 is rendered effective to force valve 10 to its illustratedright-hand limit position in which the stop 82 formed therein engagesthe plug 16.

The movement of valve 10 to its right-hand limit position interrupts thepreviously traced fluid pressure and exhaust circuits for the chamber58, and re-completes opposite circuits, through which fluid pressure issupplied to the left-hand face of vane 60, andfluid is exhaustedV fromthe right-hand face thereof. 'I'he fluid pressure supply circuit for theleft-hand face of Yvanel extends as previously stated to the main supplypassage |30. From this point the circuit extends around the valve recess88 and thro-ugh the passage |34 into the chamber-58. The exhaust circuiton the other hand extends through the passage |32, around the valverecess 84, and thence to the sump through a passage |46 whichcorresponds in all respects to the previously described exhaust passage|36. During completion of the just traced fluid circuits, accordingly,vane 60 is caused to move in a clockwise direction as viewed in Fig. 3.

g The initial movement of vane 60 away from its left-hand limit oftravel, interrupts the previously traced exhaust circuit for the valveactuating chamber 18. This action is Without effect, however, as chamber18 is now empty, and valve `10 is retained in its right-hand position bythe spring 80. As vane 60 approaches its right-hand limit of travel, thepreviously traced `fluid pressure supply circuit for valve actuatingchamber 18 is re-completed, by the movement Vof thev shaft recess |22into registry with the passages |20 and f |24.

Re-completion of thisV circuit. supplies a fluid pressure to chamber`18, Vand valve 10 is, accordingly, forced to its left-hand positionagainst the force of the compression spring Y80.

This movement of valve 10 re-completes the original fluid supply andexhaust circuits for the vane chamber 58, causing vane to stop, andre-start in the counter-clockwise direction.

As long, accordingly, as parking valve 14 and cut-off valve 12 occupythe running positions,

vane 60 continuously reciprocates between the move to its left-handlimit position. Similarly, each arrival of vane 50 at its left-handlimit position completes an exhaust circuit for the valve chamber 18,permitting valve 10 to be moved to the right under the influence of thespring 80.

Assuming that it is desired to bring the motor 50 to rest, Vthe manualvalve 14 may be moved to the left as shown in Fig. 6, to a position inwhich the recess |02 thereof is out of registry'with the supply passage||2, but is in registry with the As vane 60 approaches its right-handlimit ofk travel, the previously traced supply circuit for the reversingvalve chamber 18 is momentarily com.- pleted through the shaft recess|22. In addition, the arrival of vaneY 50 at its right-hand limit oftravel, moves the previously described radial shaft passage |40 intoregistry with the previously mentioned exhaust passage |50, which is nowin communication with the passages llland I6 through the recessedportion |02 of the manual valve 14. A fluid exhaust circuit is therebycompleted for the chamber 96 which extends therefrom through thepassages ||8 and H0, around the recessed portion |02 of valve 14andthence through the passage |50, radial shaft passageI |40, and axialshaft passage |42 into the sump. Completion of this circuit permits thespring 98 associated with the cut-off valve 12 to force the needleportion thereof into seating relation to the seat 9 thereby closing olfthe passage I8, through which passage the Vreversing valve 10, as Wellas the actuating chamber 178 thereof, are supplied. Interruption of thesupply of fluid tothe main reversing supply passagel30 causes the motorto remain at rest in the right-hand limit position and the interruptionof the supply of fluid pressure to the valve actuating chamber 18interrupts the building up of pressure'within this chamber.

The cut-off vali/e712 may readily be arranged so f that its completemovement Vto the shut off position occurs prior to anysubstantialmovement of valve 10 to the'left. When so arranged, the motor is broughtto rest with the valve 10 in its righthand position. With thispositioning, the fluid'y introduced into chamber 58 on` the left-handside in theV stopped position, and, therefore, remainsY effective topositively retain the vane in the lefthand position" and.correspondingly retain, any

Vwiper elements connected-to the motor in the limit positions.

Alternatively, the motor may be so arranged that the reversing valve 10is permitted to complete its movement to the left before the cut-offvalve 12 completes the shut off action. 'I'his may be done, as will beappreciated, by properly proportioning the passages leading into thechambers 18 and 96. In this event, at the time the motor isbrought torest, reversing valve 10 may be expected to occupy a left hand limitposition in-*readiness tocause counter-clockwise directionmofutravel,the left-hand side of vane 7s.

60 being connected to exhaust, and the right-hand side of the vane beingconnected to the vane supply inlet |30. This relation of parts, exceptfor the structural feature mentioned below, provides a positive iiuidlock for the vane 60 which retains it in the parked position, since anymovement of the vane 6 away from the parked position creates asubstantial vacuum on the righthand side of the vane 60. This fluid lockis desirable in instances where it is desired to positively retain themotor shaft in the parked position.

Alternatively, and in accordance with the illustrated form of theinvention, means may be provided to release this uid lock and permit themotor shaft to be relatively freely moved away from the parked positionby the application thereto of an external force, such as the loadconnected to the shaft.

Referring further to Figs. 6 and 8, the cut-off valve 12 is providedwith an axially extending passage |33, which communicates with a pair ofrelatively perpendicular radial passages |35 and |31 formed near theneedle valve portion thereof. In addition, the left-hand end of valve 12as viewed in Figs. 6 and 8 is provided with a breather and drain passage|3| which may extend directly to atmosphere or exhaust) As long as thecut-off valve 12 occupies the running position, both of the radialpassages |35 and |31 are blocked on" rendering the axial passage |33ineffective. In this instance the passage |3| serves merely to drainfrom the left-hand end of valve l2 any fluid which may leak around thevalve body.

Movement of the cut-off valve 12 to the stopped position shown in Fig.6, however, brings one or the other of the radial passages |35 and |31into registry with the main supply passage |30 leading to the reversingvalve 10.

Under these conditions, both sides of motor Vane 60 are connected toexhaust, one side thereof being connected to exhaust through the normalexhaust circuit, and the other side being connected to exhaust throughthe supply passage |30, radial passage |35 or |31', axial passage |33and drain or breather passage |3I. Both sides of the vane beingconnected to exhaust it will be appreciated that vane 30 and shaft 62may, accordingly, be relatively freely oscillated. If the vane 60 andshaft 62 are moved away from the normal stopped position, it is believedto be evident that these members will remain in the position to whichthey are moved since the supply circuit for the motor is positivelyinterrupted by the cut-oir valve 12. To cause the motor to return to theparked position, the manual control valve 14 may momentarily be moved tothe running position and then returned to the stopped position, theresulting operating sequence being as previously described.

Referring particularly to Figs. 11, 12 and 13, as well as to Figs. 14and 15, which correspond to Fig. 12 but show different positions of themanual valve, an embodiment of the invention is shown whichdistinguishes functionally from the previously described embodiment inthat the manual parking valve is so constructed as to be effective tocontrol the speed as well as the starting and stopping of the motor. Inall other respects except the one just noted, and except as to therespects noted below, the construction and arrangement of the motor ofFigs. 11-15 may be as described hereinbefore. Accordingly, in Figs. 11through 15, only so much of the motor is shown as is necessary toillustrate the differences, and corresponding reference characters withthe subscript a are used so far as they are applicable.

n the arrangement of Figs. 11 through 15, the previously describedparking valve 'M is replaced by a parking valve 200, similar theretoexcept that the valve 200 is provided with a tapered portion 22,disposed to control the supply of fluid to the reversing valve 10a, andconsequently to the vane chamber 58a.

In the parked position of the parking valve 200, and with the motor in aparked position, shown in Fig. 12, the chamber 93a associated with thecut-off valve 12a is connected to exhaust through a circuitcorresponding in all respects to the circuit described in connectionwith the rst embodiment. In Fig. 12, this circuit extends from thechamber 96a through a passage 204, into and around the reduced portionof the valve, through passage 206 into a radial passage |40a, and thencethrough the axial passage |42a to the sump as previously described.During completion of this circuit, accordingly, the spring 98aassociated with valve 12a is effective to retain the latter in theright-hand position. In the right-hand limit position, the land 208 ofvalve 12a closes off the main passage 2|0 leading from the inlet Illia,which action as will be appreciated from the previous description,retains the motor at rest.

Movement of the manual valve 200 to either the fast speed position shownin Fig. 14 or the slow speed position shown in Fig. 15, interrupts thepreviously traced exhaust circuit for the valve chamber 96a, andcompletes a fluid pressure supply circuit therefor which extends fromthe inlet ||4a through the passage 2I2, around the reduced portion ofvalve 200 and thence through the passage 204 into the chamber 96a.Completion of this 'circuit results in the building up of pressurewithin the chamber 96a, which forces valve 12a to its left-hand limitposition, in which the reduced portion 2|4 thereof is in registry withthe passage 2|0, and also with a main supply passage |30a. Passage |3061may correspond to the passage |30 described with reference to Figs. 1through 10, and may lead directly to the reversing valve (not shown).

In the instance being described, the passage |3011. also leads to theshaft 62a at a point axially spaced from the previously mentioned radialshaft passage Illa. The shaft 62a is provided, in axial registry withthe continuation of the passage |30a, with a radial passage 2|3 and atransverse recess 2|8. The radial passage communicates directly with thepreviously mentioned axial shaft passage |42a, leading to the sump, andthe transverse shaft recess is adapted to form a connection betweenpassage |3011 and a passage 220, which leads directly to a passage |28a.Passage |28a corresponds to the passage |28 of Fig. 3 and opens into thereversing valve actuating chamber.

With this arrangement, when the vane (not shown) reaches one limit oftravel as described with reference to Fig. 3, the shaft recess 2|8connects passages |30a and 220 together, thereby completing a fluidpressure supply circuit for the reversing valve actuating chamber whichextends from the inlet Illia.` through the passages 2|2 and 2|0, aroundthe reduced portion 2|4 of the supplemental valve 12a, passage |30a.,recess 2|8 and passages 220 and |28a into the valve chamber.

Similarly, when the vane reaches its 75 other limit of travel asdescribed with reference to Fig. 3, a fluid exhaust circuit'is providedfor the valve actuating chamber I8 which extends from the chamberthrough the passages |2861., passage 220 and thence through the radialand axial shaft passages 2|6 and 42a to the sump. In the instance nowbeing described, accordingly, the shaft passages for completing duidsupply and exhaust circuits to the reversing valve chamber are entirelyseparate and distinct from the shaft passage |40a associated with theshut-off valve 12a.

The stopping action of the motor of Figs. 11 through I5 is very similarto the stopping action of the motor of Figs. 1 through 10, and maybriefly be described as follows: Movement of the manual valve 200 to theposition shown in Fig. 12 interrupts the previously traced fluidpressure supply circuit for the valve actuating chamber 96a, andprepares an exhaust iluid circuit for this chamber through the passage206. Y This fluid exhaust circuit is, however, not completed until theradial shaft passage I 40ais brought into registry therewith, whichoccurs only when the the motor reaches the predetermined parkedposition. Pending completion of this fluid exhaust circuitaccordinglyycut-oif valve12a remains in the running position, and theonly effect upon the motor operation of the movement of the parkingvalve 200 to the parked position is to prepare the exhaust circuit. Inthe parked position of the valve 200, an unrestricted flow through thepassages 2I2 and 2I0 is provided by the annular recessed portion 22| ofthe valve. Accordingly, although the slow speed position of the valve200 is passed through in moving the valve 200 to the parking position,the motor is enabled to continue to the parking position at its maximumoperating speed. As soon as the motor approaches its selected limitposition, the radial shaft passage I 40a is moved into registry with thepassage 206, thereby completing the previously prepared fluid exhaustcircuit for the chamber 96a, and permitting the cut-off valve 12a to bemoved to its'stopping position by the spring 98a. The movement ofthervalve 12a to the stopping position brings the motor to rest in themanner described with reference to the motor of Figs. 1 through 10. n

In view of the fact that the shaft passage I40a through which theexhaust circuit for the cut-off valve 12a is completed, is entirelyindependent Aof the shaft passages 2|6 and 2|8 through which the fluidpressure supply and exhaust circuits for the actuating chamber of thereversing Valve are completed, it will be appreciated thatthe motorshaft may be caused to park in either one of its limit positions,depending upon the angular position of the radial shaft passage IIIIJa.That is, if it is desired that the shaft 62a of the motor of Figs. 11through 15 park in the same position as the shaft 62 of the motor inFigs. 1 through 10, the radial shaft passage I40a may be positioned inthe shaft as to register with the passage 205 when such parking positionis reached. On'the other hand, if it is desired that the shaft 62a parkVin the opposite position, radial shaft passage Mila may becorrespondingly positioned.

If the just mentioned opposite position is selected yas the parkingposition, it will be appreciated that the registry of passage Mila withthe passage 206 (to thereby exhaust the chamber 06a) occurssimultaneously with the registry of the radial passage 2| 6 with thepassage 220 (to thereby exhaust the reversing valve actuating shown inFig. 15, however, the tapered portion 202 is in registry with thesepassages 2| IJ and 2|2 and correspondingly restricts the flowtherethrough and, therefore, reduces the operating speed of the motor.

The embodiment of Figs. 16, 17 and 18 distinguishes principally from theembodiment of Figs. 1 through 10 in that the parking position of themotor vane is beyond the normal limit of travel thereof. In thisarrangement, with the shut off valve in the running position, the motorvane reciprocates between normal limits and, upon movement of thecut-off valve to the stop position, the vane is permitted totravel'beyond one of the4 normal limits, and is there brought to rest. Y

Except in the respects described below, the' construction andarrangement ofthe motor of Figs. 16, 17 and 18 may be and preferably isas described with reference to Figs. 1 through 10, and so far asapplicable, accordingly, corresponding reference characters, with thesubscript b, are used to designate corresponding parts.

The parts are shown in Fig. 16 in the running position of the parkingvalve 230. In this position of the parts, a fluid pressure supplycircuit extends from the inlet I|4b through the passages E32-and 231i,around the recessed portion 236 of the parking valve and thence throughpassage 238 into the valve actuating chamber 96h. During completion ofthis circuit, as Will be appreciated from the previous description, thecut-off valve '12b is retained in its illustrated left-hand position,against the force of the compression spring 08h.

As' long as the valve '12by occupies its left-hand position, the recess240 thereof is in registry with the passages 262 and 244, which connectthe inlet I |45 to the main supply passage |3019. As described Withreference to Figs. l through 10, as long as the passage |3013 issupplied with fluid under pressure, the motor is caused toy operate andto oscillate the shaft 621i in one direction or the other, dependingupon the position of the reversing valve. As in the previous embodiment,the reversing valve (not shown) is actuated to one limit position byfluid pressure, and is actuated to the other position by springpressure. In the present instance, each arrival of the motor shaft 02hat its limit position in the clockwise direction of travel moves anaxially extending peripheral recess 250 into registry with the twosupply passages 252 and 254. This action'completes Va fluid pressuresupplycircuit leading directly to the valve actuating chamber {(notshown) which circuit extends from the inlet IMU through the passages 232and 252, shaft recess 250, and passage 254 directly to the passage|281). Passage |26?) may correspond to the previously described passage4|28, and may lead directly into the reversing actuating chamber. Eacharrival of the motor shaft 62h at its clockwise limit position,accordinglyF completes the fluid pressure supply sii circuit for thereversing valve, causing it to move to the opposite limit position andreverse the direction of the movement of the motor.

On the other hand, each arrival of the motor shaft 21) at the right-handlimit of travel, moving in the counter-clockwise direction, brings thepreviously mentioned shaft recess 255i into registry with two passages262 and 262. With the cut-off valve 232 in the running position, thisaction completes the fluid exhaust circuit for the reversing valveactuating chamber, which fluid exhaust circuit extends from thepreviously mentioned passage i281) through the passage 252 (whichconnects into the passage 25B), through the shaft recess 2563, passage258, and thence around the recessed portion 224i of the cut-off valve232 to the sump through the exhaust outlet 265. It is noted, for areason discussed below, that the two passages 2S@ and 262 are slightlyangularly offset with respect to the rotation of the shaft recess 252,which recess, however, is wide enough to bridge the two passages.

Thus, each arrival of the motor shaft at its normal right-hand limit oftravel completes the exhaust fiuid circuit for the reversing valveactuating chamber, permitting the valve to be thrown to its other limitposition by the spring associated therewith. As long, accordingly, asparking valve 236 occupies the running position shown in Fig. 16, themotor shaft 22h is caused to continuously reciprocate between normalleft and right-hand limit positions, in the manner described withreference to Figs. 1 through 10 and Figs. 11 through 15.

Assuming that it is desired to bring the motor to rest, the parkingvalve 232 may be moved to the position shown in Fig. 17, in which therecess 235 thereof is out of registry with the passages 23d and 23S,thus interrupting the previously traced fluid pressure supply circuitfor the chamber 26h associated with the cut-off valve 22h. This actionalso prepares, but does not immediately complete a uid exhaust circuitfor the chamber 9519, since this exhaust circuit is dependent upon thearrival of the motor shaft at a position beyond its normal right-handlimit of travel. The only other immediate effect of the movement of theparking valve to the position shown in Fig. 17, is to prevent completionof the previously described uid exhaust circuit for the reversing valvethrough the passage 222 and 222. This is because the movement of theparking valve to the position of Fig. 17 moves the recess 2E@ out ofregistry with the passage 252, and into registry with passage 219.Accordingly, in the instance stated, the arrival of the shaft 22h at itsnormal ight-hand limit of travel does not result in a reversing movementof the reversing valve and the motor shaft continues in thecounter-clockwise direction until it reaches the position correspondingto the parked position of the shaft.

The arrival of shaft 5217 at the position corresponding to the parkedposition of the motor brings the shaft recess 252 to a postion in whichit is out of registry with the previously described exhaust passage 22d,but in which it registers with the previously mentioned passage 252, andalso registers with two additional passages 2li] and 272. As appearsmore clearly in the schematic view, Fig. 18, the two passages 2@ and 272occupy substantially the same rotative position with reference to therotation of shaft 62h, but are angularly advanced from the position ofthe passage 262. The degree of angular advance is less than the span ofthe shaft recess 252. With this relation, accordingly, shaft recess 250spans the passage 262 and the previously mentioned passage 26) when themotor shaft reaches its normal limit of travel; and interconnects thepassage 262 with both of the passages 2li)k and 272 when the motorreaches its parked position.

The movement of shaft recess 259 into simultaneous registry with thepassages 262, 270 and 272 complete a lluid exhaust circuit for thecharnber 96h associated with the cut-off valve 12b, and also connectsthe. passage l28b to exhaust. The iiuid exhaust circuit for the chamber95h extends :from this chamber through passage 272 which interconnectswith the previously mentioned passage 233, through the shaft recess 252and thence through passage 2m, valve recess 254 (which is now inregistry therewith) and through the exhaust line 255 to the sump. Theiiuid exhaust circuit for the line E231) which, as previously described,connects into actuating chamber for the reversing valve, extends fromthis passagethrough the passage 262 which interconnects therewith andthence through the shaft recess 25E! and passage 270 to the sump as justtraced. Completion of these two circuits permits the cut-off valve 12bto move to its right-hand limit position in which it stops the motor byclosing off the passage lb, as previously described; and also permitsthe reversing valve (not shown) to move to a position in readiness tobring about an opposite direction of movement upon movement of theparking valve 230 to the running position shown in Fig. 16.

As will be appreciated, the motor may be restarted by moving the parkingvalve 230 to the position in Fig. 16, thereby re-completing theinitially traced circuit for the chamber 96h and actuating the cut-offvalve 12b to the running position. As just stated, during the courseofthe stopping operation, the reversing valve (not shown) is moved to aposition in readiness to cause clockwise movement of the motor shaft andso, accordingly, the normal leftward movement of the motor shaft isbegun immediately upon the movement of the parking valve to runningposition.

The embodiment of the invention shown in Figs. 19 through 24distinguishes principally from the modification described with referenceto Figs. 1 through 9 in that the supplemental cut-olf valve is moved tothe stop position by the application thereto of fluid pressure insteadof by the application thereto of spring pressure. The movement of thecut-olf valve to running position is also effected by fluid pressure,the arrangement being such that a differential pressure is applied inorder to effect the closing movement Certain other structuraldifferences are present in the arrangement of Figs. 19 through 24, whichare noted below, but except in these respects, the arrangement andoperation corresponds to that of the rst described embodiment.Accordingly, only so much of the modified motor is shown in the drawingsas is necessary to explain the differences, and corresponding referencecharacters with the subscript c are used so far as applicable.

The parts are shown in Fig. 22 in the parked position of the parkingvalve 14C. In this positioning, a fluid supply circuit is completed forthe chamber 96C associated with the cut-off valve l2c, which fluidcircuit extends from the inlet |I4c, through the passage 290, passage292, around a transverse slot 294 formedin the shaft 62C, and thencethrough a passage 296, around Vthe recessed portion 298 of the parkingvalve, and

through passageSO into the chamber 96C. The shaft recess 294 spans thepassages 296 and 292 only when the Ymotor shaft is in the limit positionof counter-clockwise travel thereof, or considered with reference toFig. 3 in the left-hand limit position thereof.

During completion of the just traced fluid cir- Y. cuit, accordingly,the cut-olf valve '|20 is acted 10.

upon by fluid pressure which urges it to its righthand position, sho-wnin Fig. 22. At the same time, a fluid circuit is VVcomplete which tendsto move the valve to its lefthand limit position, which fluid circuitextends from the inlet ||4c through the passage 299 and connectingpassage 302 to the end of the needle valve portion 90o of the valve. Thepiston area acted upon by the fluid within the chamber 95e, however,materially exceeds the area of the needle valve portion 90e, so that the'rightward pressurev predomiparking valve '|40 to the running positionalso' interconnects the passage 396 with a supplemental passage 306which may extend directly to exhaust, thus providing an exhaust circuitfor the `chamber 96C. Upon completion of this exhaust circuit, thepressure acting upon the needle valve portion 90e of the valve 12e isrendered effective to force this valve to its left-hand limit position-shown in Fig.'21.

The movement of the cut-off valve '|2c to the running position connectsthe previously mentioned main supply passage |360 to the inlet 4c. Asdescribed with reference to the embodiment of Figs. 1 through 10, thepassage |36c may lead directly to the main reversing valve (not shown),which reversing valve acts to distribute the fluid supplied therethroughto therespectively opposite sides of the motor vane,Y depending upon theposition of the reversing valve.

` With the motorshaft 62C in the parked position shown in Fig. 22, Ythepassage |280, which as' previously described, may be connected into theactuatingchamber associated with the reviversing valve (not shown), isconnected to the sump through the axial shaft passage |420. .The circuitextends from the passage |280, Fig. 24, through passage 308, radialshaft passage |42c to the sump. This circuit as will be appreciatedr.from previous descriptionexhausts thereversing valve actuatingchamber, permitting the valve to assume a position in readiness to causeclockwise travel of the motor shaft 62C. Accordingly, upon thecompletion of the supply circuit for the main supply passage. |300, themotor is immediately caused to start in a clockwise direction from theposition shown in Fig. 22.

The. initial movement of the motor 62e away from the limit positionshown in Fig. 22 moves the transverse shaft passage 294 out of registrywith the passages 292 and 296, which action is, however, without effectsince the circuit through these passages is already interrupted at theparking valve '|4c. The initial movement of the motor vshaft 62e awayfrom theV limit position shown in ber of the reversing valve.

out of registry with the passage 368 of Fig. 24,'V

thus interrupting the just traced fluid exhaust circuit for the'mainreversing valve. This actionV is without effect, however, as thereversing valve actuating chamber may be considered as empty and thereversing valve is'held in its proper posi tion by the actuating springassociated therewith.

As the motor shaft 62o, travelling in the clockwise direction, as viewedin Fig. 22, app-roaches its clockwise limit position, the peripheral,axially extending, recess 3|!) provided therein is moved into registrywith the passage 308, and also with the passage 292. 'I'his actionconnects passage |28c to the inlet ll4c, which as will be appreciatedfrom previous description, supplies uid to the 4actuating chamberassociated with the reversing valve, causing it to move to its oppositelimit position and complete the fluid along the shaft recess 3|0, andthence through passage 308 to the passag-e |280.

'Ihe initial movement of the motor shaft 52o in the counter-clockwisedirection moves the shaftV recess 3H) out of registry with the passages292 and 308, thus interrupting the just traced fluid pressure supplycircuit for the actuating cham- This'action is without effect, however,since the interruption of this circuit serves mer-ely to trap the fluidwithin the chamber, which trapped fluid retains the valve in its properlimit position. Y

As the motor shaft 62o approaches its limit position travelling in thecounter-clockwise` direction, the radial shaft passage 3H is againbrought into registry with the passage 368, thereby re-completing thepreviously traced lluid exhaust circuit for the reversing valve chamberwhich action results in a movement of the reversing valve to a positionin which it is effective to cause clockwise travel of the motor shaft.The

arrival of the motor shaft 62o at its limit of travel in thecounter-clockwise direction also brings the shaft recess 294 intoregistry with the passages 292 and 296, tending to rfc-complete theinitially traced fluid pressure supply circuit for the control valve12C. In the operation now being described, however, it is assumed thatthe parking valve 14e is in the running position of Fig. 21, so thatcompletion of this fluid pressure supply circuit is prevented.Accordingly, as long as the parking valve '|40 occupies the runningposition, the motor shaft 62o is causedto continuously reciprocatebetween its normal clocks Vlimit position re-completes the circuit forthe chamber 96o, causing the cut-off valve TZc to move to its stopposition, and in which position it is effective to retain the motorshaft 62o at rest in its left-hand or counter-clockwise limit position.As in the previous instance, also, the

arrival of the motor shaft at its counter-clockwise limit positionre-completes the fluid exhaust circuit for the reversing valve actuatingchamber, permitting this valve to be moved to a position in which it isin readiness to cause clockwise travel of the motor shaft.

The remaining figures of the drawings, Figs. 25 through 33, illustratean embodiment of the invention in a piston type motor, in accordancewith which embodiment, also, the motor may be caused to park in a limitposition which is beyond its normal limit of travel.

Referring particularly to Figs. 2 5 through 33, the motor 326 comprisesgenerally a main casting 322, which is suitably formed to provide apiston chamber 324, the otherwise open end of which chamber is adaptedto be closed by a closure plate 326. A conventional piston 328 isslidably received within the chamber 324, and is secured to a piston rod338, which extends through a suitable bore provided therefor in thecasting 322. As will be appreciated the piston rod may be connected tothe mechanism to be actuated by the motor in any suitable manner. Inapplications of the present motor to Windshield Wiper operating systems,the preferred transmission is as disclosed in the co-pending applicationof the present applicant, Serial No. 102,098, filed September 23, 1936.

The valve mechanisms associated with the motor, in its illustratedembodiment comprise a reversing valve 332, a cut-off valve 334 and aparking valve 336. The reversing valve 332 is received in a suitablebore provided therefor in the casting 322, and is adapted to be actuatedto a position to the left of that shown in Fig. 32 by the introductionof fluid under pressure into chamber 338. Movement of the reversingvalve 332 to its illustrated right-hand limit position is effected byexhausting the fluid from the chamber 338, thus rendering a spring 343effective to move the valve to the right. The spring 343 is receivedwithin an axial bore provided therefor in the valve body and an endthereof bears against the casting 332. The cut-off valve 334 ispreferably of the type described with reference to the embodiment ofFigs. 1 through 15, and is received in a suitable bore provided thereforin the casting 322. Valve 334 is adapted to be actuated to a position tothe right of that shown in Fig. 33 by the introduction of fluid pressureinto a chamber 342 associated therewith, and is adapted to be moved tothe illustrated left-hand position by a spring 344 which is seatedbetween the endof the valve body and a bonnet 346 secured to the casting322. The parking valve 336 is slidably received in a suitable borepro-vided therefor in the casting 322, and the end thereof which extendsexternally of the motor body may be connected in any suitable Way tomanually or otherwise operated mechanism for moving the valve betweenits running and parked positions.

The remaining mechanical details of the motor, as well as thedescription of the various fluid passages formed within the motor bodyby which the starting, stopping and reversing of the motor is effectedmay best be understood with reference to a description of the operationof the motor as a whole. Throughout the following description, only theactive fluid passages are given reference characters, it beingunderstood that any indicated passages which are not given referencecharacters are dead-end passages, closed by removable plugs, which areformed as an incident to the manufacture of the active passages.

The parts are shown in the various figures in the parked position of thepiston 328, at its lefthand limit of travel, which parked position aspreviously mentioned is slightly beyond its normal limit of travel. Inthis position of the parts, the reversing valve 332 occupies itsright-hand limit position in which position it is retained by the spring343 associated therewith, and in which position, as hereinafterdescribed, it is in readiness to effect rightward movement of the piston323. With the parking valve 336 in the left-hand or parking positionshown, and with the piston 328 in its parked position, a fluid exhaustcircuit for the chamber 362 associated with the cut-off valve 334 iscompleted which circuit extends (Figs. 26, 33 and 3l) from the chamber342 through passages 353, 352 and 354, around the recess 356 of thepiston rod 333, now in registry therewith, and thence through passages358 and 366 to the recess 362 associated With the parking valve 336,which is now in registry therewith. From the recess 362, the circuitextends directly to exhaust through the passage 364. During completionof this circuit, accordingly, the cut-off valve 334 is retained in its.left-hand illustratedV position by the spring 344 associated therewith,in which position of the valve the recess 366 thereof is out of registrywith the main supply passage 368. As described hereinafter, the motorpiston is retained at rest as long as the passage 368 is closed.

During completion of the above traced fluid circuit for the chamber 342also, a fluid exhaust circuit is provided for the chamber 338 associatedwith the main reversing valve 332, which fluid exhaust circuit extends(Figs. 32, 30, 26 and 28) from the chamber 338 through the passages 310and 312, around the previously mentioned piston rod recess 356, andthence to exhaust through passage 358 as previously described withreference to the circuit for the chamber 342. During completion of thefluid exhaust circuit for the chamber 338, as will be appreciated, thespring 340 associated with the valve 332 is effective to retain thevalve in the illustrated right-hand limit position.

In order to place the motor in operation, the parking valve 336 is movedto its right-hand limit position, in which the recess 316 providedtherein is in registry with the supply passage 316, and in which therecess 362 is moved out of registry with the previously mentionedpassage 353. Movement of the parking valve recess 362 out of registrywith the passage 358 interrupts the previously traced fluid exhaustcircuit for the reversing valve chamber and for the chamber 342associated with the cut-off valve 334. Movement of the parking valverecess-314 into registry with the supply passage 316 completes a fluidsupply circuit for the chamber 342, which circuit extends (Figs. 29 and33) from the inlet 318 through passage 388, around the recess 314, andthence through passages 316, 382 and 358 into the chamber 342.Completion of this circuit admits fluid under pressure to the chamber342, accordingly forcing the valve 334 to its right-hand limit orrunning position, in which the recess 366 thereof registers with thepreviously mentioned main supply passage 368 for the motor.

Under these conditions, and with the reversing valve 332 in itsillustrated right-hand position, the chamber portion on the left-handside of piston 328 is connected to the inlet 318, and the chamberportion at the right-hand side of the piston 328 is connected toexhaust. The fluid Ychamber 338.

pressure supply circuit for the chamber4 portion at the left-hand sideof the piston extendsligs. 29, 27, 32'and 26) from the inlet 3.18,through passage 384, around the recess 386 and passages 368, 386, and388 into the chamber within which the reversing valve is positioned.With valve 332 in the right-hand'limit position, the recessV 398 thereofconnects the passage 388 with the passage 392, which, through passage384, opens directly into the chamber S24-at the left-hand side of thepiston 328. With valve 332 in the righthand position, also, the fluidexhaust circuit for the right-hand side of piston 328 extends fromchamber 324 (Fig. 32) through passage 396, `around recess 398 of valve332, and thence through passage 488 directly to exhaust. Duringcompletion, as will be appreciated, of the just traced iiuid pressuresupply and exhaust circuits, piston 328 is acted upon by a pressuredifferential which causes it to move to the right as viewed in Fig. 26.

The initial movement to the right of piston 328 moves the piston rodrecess 356 out of registry with the'previously described passage 358,which action is, however, Without effect, as the fluid Yexhaust circuitassociated with this passage is already interrupted by the parkingvalve. As the rightward movement of piston 328 continues, the piston rodrecess 356 is moved Vinto registry with the passage 482 which, ashereinafter described, re-completes a fluid. exhaust circuit for thechamber 338 associated with the reversing valve 332. This circuit is,however, without effect, since valve 332 is already in its righthandlimit position.

As piston 328 approaches its right-hand limit of travel, the piston rodrecess 356 is moved into registry with the two passages 484 and 486,(Fig. 26) which action completes .a fluid pressure supply circuit forthe chamber 338 associated with the reversing valve 332. This fluidpressure supply Vcircuit extends (Figs. 29, 26 and 32) from the inlet318, through passage 384, cut-off valve recess 366, passageV 368,passage 486, piston rod recess 356, and passage 484 directly into thechamber 338. Completion of this circuit accordingly admits fluid underpressure to the reversing valve actuating chamber, causing the valve tomove to its left-hand limitV position, in which position the recess 388connects the passage 392 to exhaust through passage 488, and connectsthe passage 396 to the supply passage 388. In the just stated left-handlimit position of the valve, also, the passage 392 is closed ofr` fromthe inlet 388, and the exhaust passage 488 is rendered ineffective. Itis believed to be evident that with the reversing valve in the left-handposition as just stated, the fluid pressure supply and exhaust circuitsfor the piston chamber 324 are the reverse of those previously stated,resulting in movement to the left of the piston 328.

The initial leftward movement of piston 328 moves the piston rod recess356 out of registry with the passages 484 and 486, interrupting the justtraced fluid pressure supply'circuit for the Y This action is withouteiectupon the positionV of the valve, however, since the fluidpreviously introduced into this chamber remains trapped therein, andholds the valve in the lefthand limit position. v

As the'piston 328 approaches its normal lefthand limit of travel, thepiston rod recess 356 is moved into registry with the previouslymentioned passage 482 and a cooperating passage 418, which actionre-completes the fluid exhaust circuit for the reversing valve 338. Thisiluid exhaust circuit extends (Figs. 32, 26, 28 and 31) from the chamber338, passage 318, connecting passage 412', passage 4l8, recess 356, andthence through passages 482 and 414, around the parking valve recess362V (now in registry therewith) and pas*- sage 416 to exhaust. Uponcompletion of'this circuit, the lluid previously delivered to thechamber 338 is discharged therefrom and. the reversing valve 332 causedto resume its illustrated right-hand limit position under the influenceof the compression spring 348 associated therewith. The movement of thereversing valve to its righthand limit position restores the originalfluid pressure supply and exhaust circuits for the piston chamber 324,causing the piston Yto stop and restart in the rightward direction. 'Ihereversing action at the right-hand limit of travel is,` of course, aduplicate of that'previously described.

It will be appreciated, accordingly, thatk as long as the parking valve336 occupies the running position in which the recess 362 thereofregisters with` the passage 416, the piston continuously reciprocatesbetween a left-hand limit position in VVwhich the piston rod recess 356registers with the passages '418 and 482, and a right-hand limitposition in which the piston rod. recess 356 regirsters with thepassages 484 and 486.

In order to bring the motor to rest at its illustrated left-hand limitposition (Fig. 26) the parking valve 336 is moved to the position shownin Fig. 31, in which the recess 362 is out of registry with the passage4I6 and is in registry with the passage 358. In this position, also,recess 314 is out of registry with the main supply passage 316.

The movement of the parking Valve recess 314 out of registry with thesupply passage 316 interrupts the previously traced fluid pressuresupply circuit for the chamber 342 associated with the cut-off Valve334. A fluid exhaust circuit for this chamber,l however, is vnotcompleted until-the piston 328 reaches the position shown in Fig. 26

so that the movement of the parking Valve toV the stopping position hasno immediate elect up on the movement of the piston. v

If the parking valve 336 is moved to the stopping position duringrightward travel of the piston 328 it is believed obvious that a normalreversal at the right-hand limit of travel will occur. If the parkingvalve 336 is-moved to the stopping position during leftward travel ofthe piston 328, no effect upon movement of the piston results until thepiston reaches the position shown in Fig. 26. During such nal leftwardmovement,V

the pistonrod recess 356 is moved into registry with the passage 4 I 8,tending to complete the previously traced exhaust circuit for thechamber 338. Completion of this exhaust circuit, however, is preventedsince the passage 4|6 is now closed by the parking valve 336. Noreversing movement of the reversing valve 332 occurs at the normalleft-hand limit of travel of the piston accordingly, and the pistoncontinues its leftward movement beyond such normal left-hand position.Asthe piston approaches the position shown in Fig.- 26, the piston rodrrecess 356 is moved into registry with the previously mentioned passage358, thereby simultaneously completing a fluid exhaust circuit for thereversing valve chamber 33B, and a fluid exhaust circuit for the chamber342 associated with theY cut-off valve 334.

Y The fluid exhaust circuit for the chamber 342 extends as described atthe beginning of the present description of operation. Completion ofthis circuit permits valve 334 to resume the illustrated position underthe influence of the spring 344, in which the main supply passage 368 isclosed, causing the piston 328 to remain at rest. The uid exhaustcircuit for the reversing valve chamber 338 extends (Figs. 32, 26, 31and 30) from the chamber 338, passages 310, 412 and 372, around thepiston rod recess 356, and thence through passages 358 and SEU aroundthe parking valve recess 362 and passage 364 to exhaust. Completion ofthis circuit permits the reversing valve 332 to resume the right-handlimit position shown in Fig. 32, in which position it is in readiness tocomplete the uid circuit for the piston chamber to cause rightwardmovement thereof.

Although specific embodiments of the present invention have beendescribed in detail, it will be appreciated that various modificationsin the form, number and arrangement of the parts thereof may be madewithin the spirit and scope of the present invention.

What I claim is:

1. Fluid pressure operated motor mechanism comprising, in combination, amember movable under the influence of differential pressure; meansincluding a iiuid circuit and a reversing valve mechanism forcontrolling the application of said differential pressure to saidmember; and stopping mechanism for said motor including fluid pressureoperated valve means controlled in accordance with the position of saidmember for controlling said fluid circuit.

2. Fluid pressure operated motor mechanism comprising, in combination, amember movable under the influence of a fluid pressure differential;means including a pressure supply circuit and a reversing valvemechanism for controlling the application of said differential pressureto said member; and means for bringing said motor to rest including uidpressure operated valve mechanism movably responsive to the position ofsaid member for controlling said supply circuit.

3. Fluid pressure operated motor mechanism comprising, in combination, amember movable under the inuence of a fluid pressure differential;reversing valve mechanism for controlling the direction of movement ofsaid member; a fluid pressure operated cut-oif valve for controlling theapplication of said fluid pressure differential to said motor; andstopping means for said motor rendered effective in accordance with theposition of said member for controlling said cut-off valve.

4. Fluid pressure operated motor mechanism comprising, in combination, amember movable under the influence of a fluid pressure difieren tial; areversing valve mechanism for controlling the direction of movement ofsaid member; a pressure supply line leading to said motor; a fluidpressure operated cut-off valve disposed to open and close the supplyline; and stopping mechanism for said motor controlled in accordancewith the position of said member for actuating said cut-off valve.

5. Fluid pressure operated motor mechanism comp-rising, in combination,a member movable under the influence of a fluid pressure differential;reversing valve mechanism for controlling the direction of movement ofsaid member; uid circuit means for contro-lling the application of saidfluid pressure dierential to said motor; a fluid pressure operatedcut-off valve disposed to open and close said circuit means; and meansincluding a. selectively operabie stopping valve rendered effective inaccordance with the position of said member for actuating said cut-offvalve.

6. Fluid pressure operated motor mechanism comprising, in combination, amember disposed to be moved under the influence of a fluid pressurediierential; reversing valve mechanism for controlling the direction ofmovement of said member; fluid circuit means for controlling theapplication of said fluid pressure differential to said motor; a fluidpressure operated cut-olf valve for opening and closing said circuitmeans; and a fluid circuit for said cut-olf valve controlled inaccordance with the position of said member.

7. Fluid pressure operated motor mechanism comprising, in combination, amember disposed to be reciprocated under the influence of a fluidpressure differential; reversing valve mechanism for controlling thedirection of movement ofsaid member; fluid circuit means for applyingsaid fluid pressure differential to said motor; a fluid pressureoperated cut-off valve for opening .and closing said circuit means; astopping valve; and a fluid actuating circuit for said cut-ofi" valvecontrolled jointly by said stopping valve and by the position of saidmember.

8. Fluid pressure operated motor mechanism comprising, in combination, amember disposed to be reciprocated between predetermined limits underthe influence of a fluid pressure differential; reversing valvemechanism for controlling the direction of movement of said member;means including a fluid circuit for applying said fluid pressuredifferential to said motor; a cut-olf valve for opening and closing saidcircuit; and stopping means for said motor disposed to delay operationof said reversing valve mechanism and to cause said member to be movedto a position beyond said limit and be stopped by said cut-off valve.

9. Fluid pressure operated motor mechanism comprising a member disposedto be moved under the influence of a fluid pressure differential betweennormal limits and to a position beyond one of said normal. limits;reversing valve mechanism normally effective to reverse said member atsaid normal limits; cut-01T valve mechanism for stopping said motor; anda selectively operable stopping device operable to delay operation ofsaid reversing mechanism at one of said limits and to cause said memberto move to and be stopped at said further position by said cut-offvalve.

10. Fluid pressure operated motor mechanism comprising, in combination,a member disposed to be moved under the influence of a fluid pressuredifferential between a rst and second limit positions and a stoppingposition beyond said second limit position; reversing valve mechanismfor said motor normally eifective to reverse said member at said secondlimit position; .a cut-off valve for stopping said motor at saidstopping position; and a selectively operable stopping device fordelaying operation of said reversing mechanism and for actuating saidcut-off valve to cause said motor to stop at said stopping position.

11. Fluid pressure operated motor mechanism comprising, in combination,a member disposed to be moved under the inuence of fluid pressurebetween first and second normal limit positions and a stopping positionbeyond said second limit position; reversing valve mechanism normallyeffective to reverse said member at said second limit position; acut-oif valve for stopping said motor; .and a selectively operablestopping device operable at any time during the movement of said memberforvdelaying operation of-.said

reversing valve and for rendering said cut-'off valve effective to stopsaid motor at said stopping position.

12. Fluid pressure operated motor mechanism comprising, in combination,a member disposedl to be reciprocated under the influence of Va fluidpressure differential between first and second normal limit positionsand movable toA a stopping position beyond said second limit position;re- Versing valve mechanism normally effective to reverse said motor atsaid second limit position; a cut-off valve for stopping said motor; anda selectively operable parking stopping device rendered effective inaccordance with the position of said member for delaying the operationof said reversing valve mechanism and for rendering said cut-off valveeffective to stop said motor at said stopping position.

13. Fluid pressure operated motor mechanism comprising, in combination,a member disposed to be moved under the influence of a fluid pressuredifferential between first and second limit positions and to astoppingposition beyond said second limit position; a fluid pressure actuatedreversing valve mechanism normally effective to reverse said motor atsaid' second limit position; a fluid pressure operated cut-olf valve forstopping said motor; a fluid circuit for said reversing valve mechanism;a fluid circuit for said cutoff valve; and means including a selectivelyoperable stopping device operable to control said fluid circuit tothereby delay the operation of said reversing valve and to render saidcut-off valve effective to stop said motor at said stopping position.

14. Fluid pressure operated motor mechanism comprising, in combination,a member disposed to be moved under the influence of a fluid pressuredifferential between first and second limit positions and to a stoppingposition beyond said second limit position; a fluidkpressure actuatedreversing valve mechanism normally effective to reverse said motor atsaid second limit position; a fluid pressure operated cut-off Valve forstopping said motor'; a fluid circuit for saidreversing valve mechanism;a fluid circuit for said cut-off valve; and means including selectivelyoperable stopping device rendered effective by movement of said memberfor controlling said fluid circuits to thereby cause said member to moveto and stopat said stopping position. Y

V15. Fluid pressure operated motor mechanism comprising, in combination,aY member disposed to be moved under the influence of a fluid pressuredifferential; reversing valve mechanism for controlling the direction ofmovementV of said member; a cut-off valve for controllingY theapplication to said motor of said fluid differential; spring-means forurging said cut-oil valve to one of said positions; fluid pressure meansfor actuatingsaid cut-olf valve to the other of said positions; and aselectively operable stopping device for said motor for controlling saidfluid pressure means.

16. Fluid pressure operated motor mechanism comprising, in combination,a member disposed to be moved under the influence of a fluid pressuredifferential; reversing valve mechanism for controlling the direction ofmovement of said member; a cut-off valve for controlling the appli-VYcation to said motor of said fluidv differential;

vice controlled in accordance with the position of said member forcontrolling said fluid pressure means.

17. Fluid pressure operated motor mechanism comprising, in combination,a member disposed to be moved under the influenceY of a fluid pressuredifferential; fluid pressure operated reversing'valve mechanism forcontrolling the direction of movementV of said member; a fluid pressureoperated cut-off valve actuable to control the application of said fluidpressure differential to said motor; a fluid circuit for said reversingvalve mechanism; a fluid circuit for said cut-off valve; and valvepassage means common to said fluid circuits and disposed to be openedand closed by movement of said member.

18. Fluid pressure operated motor mechanism comprising, in combination,a member disposed to be moved under the influence of a fluid pressuredifferential; fluid pressure operated reversing valve mechanism forcontrolling the direction of movement of said member; a fluid pressureoperated cut-off valve for controlling rthe application to said motor ofsaid fluid pressure differential; a fluid circuit for said reversingvalve mechanism; a fluid circuit for said cut-off valve;

and fluid passages individual to said fluid circuits and disposed to beopened and closed by movement of said member.

19. Fluid pressure operated motor mechanism comprising, in combination,a member disposed to be moved under the influence of a fluid pressuredifferential; fluid pressure operated reversing valve mechanism forcontrolling the direction of movement of said member; a fluid pressureoperated cut-off Vvalve for controlling the application to said motor ofsaid fluid pressure differential; a fluid circuit for said reversingvalve mechanism; a fluid circuit for said cut-off va1ve;' Y

for said reversing valve mechanism; and means including a selectivelyoperable control device for said motor and effective when in oneposition to cause completion of said fluid circuit when said memberreaches that'said second limit position and effective when in anotherposition to cause completion of said fluid circuit when said memberreaches said stopping position.

21. Fluid pressure operated motor mechanism comprising, in combination,a member disposed to be moved under the influence of a fluid pressuredifferential between rst and second limit positions and a stoppingposition beyond said second limit position; fluid pressure operatedreversing valve mechanism for controlling the direction of movement ofsaid member; a first fluid circuit disposed to be completed when saidmember reaches said second limit position for actuating said reversingvalve mechanism; a secondfluid circuit disposed to be completed whensaid member reaches said stopping position for actuating said reversingvalve mechanism; and a selectively operable control device fordetermining which of said fluid circuits is to be effective.

22. Fluid pressure operated motor mechanism comprising, in combination,a member disposed to be moved under the influence of a fluid pressuredifferential between first and second limit positions and a stoppingposition beyond said second limit position; iiuid pressure operatedreversing valve mechanism for controlling the direction of movement ofsaid member; a first fluid circuit disposed to be completed When saidmember reaches said second limit position for actuating said reversingvalve mechanism; a second iluid circuit disposed to be completed whensaid member reaches said stopping position for actuating said reversingvalve mechanism; a selectively operable control device for determiningwhich of said fluid circuits is to be effective; and a cut-off valve forstopping said motor at said stopping position. A

23. Fluid pressure operated motor mechanism comprising, in combination,a member disposed to be moved under the influence of a iiuid pressureldiiferential between first and second limit positions and a stoppingposition beyond said second limit position; iiuid pressure operatedreversing valve mechanism for controlling the direction of movement ofsaid member; a first fluid circuit disposed to be completed When saidmember reaches said second `limit position for actuatingsaid reversingvalve mechanism; a second iluid circuit disposed to be completed whensaid member reaches said stopping position for actuating said reversingvalve mechanism; av selectively operable control device for determiningwhich of said fluid circuits is to be elective; and a cut-off valveresponsive to said control device for stopping said motor at saidstopping position.

HUMPHREY F. PARKER,

